Quick Answer. A low hemoglobin count, also known as anemia, is caused by pregnancy, a menstrual period, a diet low in iron, blood loss, or a disease that causes the body to produce fewer red blood cells or to destroy red blood cells. According to the Mayo Clinic, medications also sometimes cause anemia.
A cytotoxic T cell (also known as TC, cytotoxic T lymphocyte, CTL, T-killer cell, cytolytic T cell, CD8+ T-cell or killer T cell) is a T lymphocyte (a type of white blood cell) that kills cancer cells, cells that are infected (particularly with viruses), or cells that are damaged in other ways.
helper T cell. helper T cell n. Any of a class of T cells that are activated by interacting with antigen-presenting cells, such as a dendritic cells, and then function to activate other cells of the immune system, including B cells, cytotoxic T lymphocytes, and phagocytes. Activated helper T cells usually have CD4 receptors on the surface. Also called T-helper cell. helper T cell n.